Can you provide some other, possibly less obvious use cases for structured bindings? How else can they improve readability or even performance of C++ code? More in general, you can use it to (let me say) unpack a structure and fill a set of variables out of it: struct S { int x = 0; … Read more
In the structure bindings paper: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0144r2.pdf they discuss their reasoning: 3.8 Should there be a way to explicitly ignore components? The motivation would be to silence compiler warnings about unused names. We think the answer should be “not yet.” This is not motivated by use cases (silencing compiler warnings is a motivation, but it is … Read more
The structured bindings proposal contains a dedicated section answering your question (P0144R2): 3.8 Should there be a way to explicitly ignore components? The motivation would be to silence compiler warnings about unused names. We think the answer should be “not yet.” This is not motivated by use cases (silencing compiler warnings is a motivation, but … Read more
I wrote this yesterday: decltype(x), where x is a structured binding, names the referenced type of that structured binding. In the tuple-like case, this is the type returned by std::tuple_element, which may not be a reference even though the structured binding itself is in fact always a reference in this case. This effectively emulates the … Read more
Core issue 2313 changed the standard so that structured bindings are never names of variables, making them never capturable. P0588R1‘s reformulation of lambda capture wording makes this prohibition explicit: If a lambda-expression […] captures a structured binding (explicitly or implicitly), the program is ill-formed. Note that this wording is supposedly a placeholder while the committee … Read more